The present invention relates generally to microsurgical and ophthalmic systems, and more particularly to a foot pedal assembly for use with a control system for operating microsurgical instruments.
Ophthalmic microsurgical systems provide one or more pneumatically operated (fluid pressure operated) surgical instruments connected to a control console. The control console provides the fluid pressure signals for operating the instruments and usually includes several different types of human actuable controllers for controlling the fluid pressure signals supplied to the surgical instruments. Usually included is a foot pedal assembly which the surgeon can use to control a surgical instrument.
Conventional foot pedal assemblies use a variety of pneumatic and electrical actuators to control microsurgical instruments. In pneumatic foot pedal assemblies, pneumatic fluid enters the foot pedal assembly through an inlet port which is connected to a pneumatic supply. The amount of pneumatic fluid leaving the foot pedal assembly is proportional to the amount of depression on the foot pedal of the assembly. The larger the depression on the foot pedal, the greater the amount of pneumatic fluid which is delivered to the control console from the foot pedal assembly. Foot pedal assemblies which employ electrical actuators use a potentiometer which is attached to the pedal. As the pedal is pivoted by the operator, the resistance of the potentiometer changes. This change in resistance is used by the control console to generate a signal for adjusting the microsurgical instruments.
While conventional foot pedal assemblies have helped to make microsurgery and ophthalmic surgery possible, these assemblies are not without drawbacks. Such foot pedal assemblies often become inoperable when they were exposed to saline, which is used in ophthalmic microsurgical procedures, and therefore were often unreliable over an extended period of time. In addition, because such foot pedal assemblies provided an analog input to the control console, the foot pedal assemblies were not generally capable of providing a high resolution positional signal that would otherwise be possible with a digitally encoded signal. Furthermore, the use of an analog input made it necessary to calibrate each foot pedal to a specific control console. Finally, the cable from the control console to electrically activated foot pedal assemblies often had to be relatively short as the resistance of the cable had to be below a preselected level to comply with certain equipment specifications.
The present invention greatly advances the art by providing a foot pedal assembly which delivers an optically encoded signal to a of microsurgical or ophthalmic system which is responsive to the degree depression of the foot pedal. By optically encoding the degree of depression of the foot pedal, the resolution of the movement of the foot pedal may be adjusted to accommodate a variety of surgical techniques. In addition, the foot pedal is less susceptible of becoming inoperative when it is exposed to saline during surgical procedures. Furthermore, since a digitally encoded input is used, there is no need to calibrate each foot pedal to a specific control console. Finally, since the present invention does not use electrical cables between the foot pedal assemblies and the control console, the cables may be longer than would otherwise be acceptable.
More specifically, the foot pedal assembly according to the present invention is adapted for remotely controlling microsurgical instruments. The foot pedal assembly comprises a base member upon which a foot pedal is mounted. The foot pedal assembly also comprises means for providing an optically transmitted signal for use in controlling the microsurgical instrument in response to the movement of the foot pedal.
In further accordance with the invention, the foot pedal is mounted on one end of the base member for pivotal movement in a general vertical direction. The foot pedal assembly also includes a rotating optical encoder for providing a digitally encoded signal which is optically transmitted to the control console for controlling the microsurgical instrument.
Still further in accordance with the present invention, the optically transmitted signal comprises a plurality of individual light conveying channels. The means for providing an optically transmitted signal may also include an optical fiber conduit for defining each of the light channels and for transmitting light from the base to the plurality of light conveying channels. These fiber optic conduits eliminate the need to supply electricity to the foot pedal, and they also eliminate the need for pressure sensitive pneumatic piping as well. Accordingly, the present invention provides an effective, durable device for conveying signals to the surgical controller.
For a more complete understanding of the invention, its objects and advantages, reference may be made to the following specification and to the accompanying drawings.